Abstract
An operator had live perforating guns stuck in the casing at 14,100 ft. The wireline had been pulled out of the rope socket, leaving 67 ft of wireline tools, perforating guns, and plug assembly stuck in the wellbore with 8,300-psi surface pressure. To remediate this issue, a 144-ft tall snubbing unit rigup was employed using eleven 7 1/16-in. 15K-psi blowout preventer (BOP) cavities and 78 ft of riser spool. Job preparation included standard prejob planning analysis to help resolve work string buckling risks and to establish the work string’s maximum safe load limits based on the well conditions and operational requirements.
This challenging high-pressure fishing job was executed as planned and without incident. The snubbing unit was rigged up, pressure tested, and operational within five days of equipment arriving on location. The snubbing unit crew successfully latched and recovered 97 ft of fish and work string bottomhole assembly (BHA) to surface under high pressure without incident.
This paper explores the level of prejob due diligence analysis required for the basic planning of high-pressure snubbing work. Surface buckling analysis, work string condition, and pipe tension/collapse considerations are applied and discussed in this case history.
